1. Cryogenics for sc links, a short update
S. Claudet, CERN-TE-CRG
6th HiLumi annual meeting, Paris Nov 2016

2. Cryogenics for sc links, short update
Content
Recall basic cooling principles & schemes
Various types of sc-links and cooling
Summary
SC - 15Nov'16
Cryogenics for sc links, short update

3. Cryogenics for sc links, short update
Where do we stand
Specific cooling schemes mostly extracted from MS57 reference document integrated in HILUMILHC-Del-D6-2-V0
No new work done on cooling principles since sc-links integration in underground areas
Only minor contributions mostly for alternatives around Q4-Q5-Q6 with the aim to re-use existing DFBL’s
SC - 15Nov'16
Cryogenics for sc links, short update

4. Baseline as presented in “HILUMILHC-Del-D6-2-V0”
Schematic & work by Udo Wagner, 2014
Any special requirement for operating modes ?
- Cool-down: conductor cooling 1st, then shield, or tentatively all at the same time, or … ?
- 20K or 80K shield (stand-by?)
Scheme for LTC secondary link (baseline) ?
NEW,
To ensure correct cooling of LTC link in case of perturbation of Line_C temperature
Some of the concerns (shield, transients, local heat loads) are still present and should be studied and treated in 2017
SC - 15Nov'16
Cryogenics for sc links, short update

5. Arc feed box Same principle to be applied for new triplets
Simplified scheme of a DFA box to replace DFBA next to Q7,
+ Many circuits RB, IPQ, correctors
+ Delicate interface with arc termination module to be looked at
Same principle to be applied for new triplets
SC - 15Nov'16
Cryogenics for sc links, short update

6. HiLumi Triplet R5 flow scheme
sc link
SC - 15Nov'16
Cryogenics for sc links, short update

7. P1/P5 Cryogenic architecture
18 kW equivalent at 4.5 K, including 3 kW at 1.8 K
Warm compressor station
SHE
Following Cost to Performance exercise Summer 2016 (Performance - Cost - Risk)
QSVB
GHe storage tanks
Surface piping
SHM
QSCG
QSAG
Dryer
QSP
Surface cold box
SLN SD
SLN
Quench tank
QSDQ
QSRG
QSDN
Liquid Nitrogen tanks
Surface
Shaft
QPP
QPLG
Vertical transfer line
Underground US
Cold compressors box
QURCG
DFHX
DFHM
(existing)
DFBL UR UL
QUIG
DSHX
DSHM
DSL
LHC tunnel
Interconnection box Q1
Q2a
Q2b Q3 CP D1 D2 CC CC Q4 Q5 Q6
QRP
QXL
Studies on-going for sc links
HRL
18Oct'16
HiLumi Cryogenics (WP9) for 2nd C&S_Review_Oct'16

8. P1/P5 Cryogenic architecture
18 kW equivalent at 4.5 K, including 3 kW at 1.8 K
Following Cost to Performance exercise Summer 2016 (Performance - Cost - Risk)
1. Main sc link,
cooling flow driven by large currents
2. sc-link for D2,
Not yet finalised,
lower current w.r.t length
3. sc-link for Q4-Q5-Q6,
under study depending on correctors (number, current rating, proven solutions)
Underground US
Cold compressors box
QURCG
DFHX
DFHM
(existing)
DFBL UR UL
QUIG
DSHX
DSHM
DSL
LHC tunnel
Interconnection box Q1
Q2a
Q2b Q3 CP D1 D2 CC CC Q4 Q5 Q6
QRP
QXL
Studies on-going for sc links
HRL
18Oct'16
HiLumi Cryogenics (WP9) for 2nd C&S_Review_Oct'16

9. 1. Main sc-link D1-CP-Triplet
Principle of DFX identified, but double splice (MgB2-NbTi, NbTi-Nb3Sn) and plug to be studied in more details
Needs for beam screen (or not) to be made
Needs for 20K shield to be clarified:
Obvious gain in flexibility without thermal shield
Risk of local “hot spots”, like seen in some bends of existing DFBLC
Specific configuration of cable in helium jacket to be carefully looked at, like with double inverted helical spacers
SC - 15Nov'16
Cryogenics for sc links, short update

10. Cryogenics for sc links, short update
2. sc-link for D2
DFHM
Not the most advanced due to recent baseline changes, and to integration of intermediate box DFM
Cooling margin of the link to be assessed, as same length but lower current rating than main sc-link
Same consideration for thermal shield as for main link D2
QXL
SC - 15Nov'16
Cryogenics for sc links, short update

11. Cryogenics for sc links, short update
3. sc-link for Q4-Q5-Q6
Under study, based on required correctors (number and current rating) and considering number of existing leads in DFBL and present solutions for local powering
With options considered for Q4, would be wise to consider a powering scheme that would not require a modification of the DSL link in the future
(existing)
DSL Q4 Q5 Q6
QXL
Difficult to imagine removing the existing QRL and installing new QXL and other hardware while keeping existing DSL link in place, but we will see when studied more advanced
SC - 15Nov'16
Cryogenics for sc links, short update

12. RR Present DSL link QRL supply DFBL with cold He (blue)
DFBLD supplies current leads over DSL (orange)
HL-LHC-DFBs will be on the new service tunnel and will have DSLs to the SAMs
On the HL-LHC, the direction of the He flow to cool the current leads will be different:
LHC: QRL-DFBL-DSL-Magnet
HL-LHC: Magnet-DSL-DFBL-WarmRecovery

13. LHC situation of DSL_L5 Q6
QRL ARC S4-5
DSL Q6
New QXL LSS5L
From DFBL_
Currently it is a SM type DC at 7L5
Return modules
Currently SM (at 7L5) receives current leads from DFBLD and delivers DSL. This will be removed. The DFBL and DSL will be routed diferently.
The new available space will be used for a special ServiceModule (at 7L5). It will be a kind of „QUIC“ to connect QRL S4-5 and QXL S5 (in other words Refr4-5 and Refr5) in case of need.
DSL coming from DFBLD and connected to Q4L5-D2L5 (orange)
SM cools the magnets independently from the current leads coming from the DSL (blue)

14. LHC - Existing solutions
Not shielded
Fed by link
OK for 6kA
Not shielded
3 circuits (bus, LHe-GHe)
Low point with splice & plug (as for DFBA’s)
Adapted to magnet 1.9K
Need for thermal shied to be evaluated

15. Cryogenics for sc links, short update
Summary
The sc-link cooling principles were defined with the basic original cooling schemes. It is now time to update all that to match the 3 types (Triplet-D2-SAM)
The use of thermal shield is clearly a safe baseline, but alternative no-shield could be envisaged only if a specific effort is made on spacers to avoid hot spots
Many technical solutions combining cooling and powering were developed for LHC and have proven to provide required performance. We will have to review what deserves to be adapted and what needs new developments
SC - 15Nov'16
Cryogenics for sc links, short update